Brake system

Abstract

To provide a brake device which can arbitrarily change a relation between tread force input to a brake pedal, and thrust transmitted to an input rod.SOLUTION: A brake device 1 has: a guide rail 51 which is provided on a pedal arm 26a, and extends in a longitudinal direction of the pedal arm 26a; a slider 52 which is connected to the pedal arm 26a through the guide rail 51, and is movable on the guide rail 51; and a connection arm 53 whose one end is rotatably connected to the slider 52, and the other end is rotatably connected to an input rod 28.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a brake device having a mechanism capable of changing the lever ratio of a brake pedal. [Background technology]

[0002] 2. Description of the Related Art Generally, a braking device mounted on a vehicle such as an automobile is provided with a brake booster (vacuum booster) which is a boosting device that amplifies brake fluid pressure by utilizing negative pressure generated in an engine or the like.

[0003] In such brake devices, a countermeasure is required in the event of a malfunction, such as an inability to store an appropriate negative pressure in the brake booster. To address this issue, for example, Patent Document 1 discloses a technology for changing the pedal ratio (lever ratio) of the brake pedal, which is expressed as the ratio between the rotation radius of the pedal and the rotation radius of the connection between the pedal and the clevis, by changing the position of the rotation support shaft of the brake pedal. In the technology disclosed in Patent Document 1, in the event of a malfunction of the brake booster, the position of the brake pedal rotation shaft is switched toward the connection between the pedal and the clevis, increasing the lever ratio, thereby inputting a large thrust force to the input rod in response to the brake pedal pressure. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 9-328061 Summary of the Invention [Problem to be solved by the invention]

[0005] However, the technology disclosed in the above-mentioned Patent Document 1 employs a configuration in which the effective length of the brake pedal is shortened to increase the lever ratio, which may make it difficult to effectively utilize the entire length of the brake pedal in the event of a malfunction.

[0006] In addition, in this type of brake device, it is desirable to be able to variably set the relationship between the brake depression force and the thrust force in response to the driver's request, etc., even when the device is not malfunctioning, thereby changing the feeling of braking operation.

[0007] The present invention has been made in consideration of the above circumstances, and aims to provide a brake device that can arbitrarily change the relationship between the force input to the brake pedal and the thrust transmitted to the input rod. [Means for solving the problem]

[0008] A brake device according to one aspect of the present invention includes a brake pedal that is rotatable around an arm rotation shaft provided at one end of a pedal arm as a fulcrum, an input rod to which a pedal force input to the brake pedal is transmitted as a thrust, and a master cylinder that generates a brake fluid pressure corresponding to the thrust input to the input rod. a guide rail provided on the pedal arm and extending along the longitudinal direction of the pedal arm; a slider connected to the pedal arm via the guide rail and movable on the guide rail; and a connecting arm having one end rotatably connected to the slider and the other end rotatably connected to the input rod; a vacuum type brake booster that increases the thrust transmitted to the input rod, a vacuum sensor that detects the vacuum introduced into the brake booster, and control means that controls the moving position of the slider relative to the guide rail; Equipped with The control means moves the slider toward the arm rotation shaft when the negative pressure detected by the negative pressure sensor is less than a preset threshold value. It is something. [Effects of the Invention]

[0009] According to the brake device of the present invention, the relationship between the depression force input to the brake pedal and the thrust force transmitted to the input rod can be changed as desired. [Brief explanation of the drawings]

[0010] [Figure 1] Schematic diagram of the brake system installed in the vehicle [Figure 2] Side view of brake pedal mechanism [Figure 3] FIG. 1 is a side view of the brake pedal mechanism when the slider is moved toward the pedal pivot shaft. [Figure 4]A side view of the brake pedal mechanism when the slider is moved toward the foot pedal. [Figure 5] 1 is a schematic diagram of a slider mechanism showing a part of the slider in fragmentation; [Figure 6] Flowchart showing slider position control routine [Figure 7] FIG. 10 is a side view of a brake pedal mechanism according to a modified example. DETAILED DESCRIPTION OF THE INVENTION

[0011] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the accompanying drawings, in which: Figure 1 is a schematic diagram of a brake device mounted on a vehicle according to an embodiment of the present invention;

[0012] 1 is mounted on a vehicle M such as an automobile. The brake device 1 includes friction brakes 6fl, 6fr, 6rl, and 6rr provided on left and right front wheels 5fl and 5fr and left and right rear wheels 5rl and 5rr of the vehicle M, a brake actuator 7 that supplies hydraulic fluid pressure to each of the friction brakes 6fl, 6fr, 6rl, and 6rr, and a brake control unit (BCU) 8 that serves as control means for controlling the brake actuator 7.

[0013] Each of the friction brakes 6fl, 6fr, 6rl, and 6rr includes, for example, a disc rotor 9fl, 9fr, 9rl, and 9rr provided on each of the wheels 5fl, 5fr, 5rl, and 5rr, and a caliper 10fl, 10fr, 10rl, and 10rr. Each of the calipers 10fl, 10fr, 10rl, and 10rr includes, as a friction engagement element, a brake pad (not shown) that engages with the corresponding disc rotor 9fl, 9fr, 9rl, and 9rr.

[0014] A brake actuator 7 is connected to each of the calipers 10fl, 10fr, 10rl, and 10rr of the friction brakes 6fl, 6fr, 6rl, and 6rr.

[0015] The brake actuator 7 includes a brake pedal mechanism 15 and a brake fluid pressure circuit 16 connected to the brake pedal mechanism 15, which constitutes a main part of the brake actuator 7.

[0016] The brake pedal mechanism 15 includes a master cylinder 24 , a reservoir tank 25 attached to the master cylinder 24 , a brake pedal 26 , and a brake booster 27 interposed between the brake pedal 26 and the master cylinder 24 .

[0017] The reservoir tank 25 stores a pressure medium (fluid).

[0018] A vacuum line 27a is connected to the brake booster 27. A vacuum source, for example, an engine intake manifold (not shown), is connected to the vacuum line 27a. A brake pedal 26 is connected to the brake booster 27 via an input rod 28. A slider mechanism 29, which will be described later, is interposed between the input rod 28 and the brake pedal 26.

[0019] The depression force input to the brake pedal is transmitted to the input rod 28 as a thrust (pressing force) in the longitudinal direction of the input rod 28. The brake booster 27 uses the negative pressure supplied from a negative pressure source as a power source to generate a brake assist force in response to the thrust transmitted to the input rod 28. In other words, the brake booster 27 amplifies the thrust transmitted to the input rod 28. The brake booster 27 then transmits the amplified thrust (the resultant force of the thrust transmitted to the input rod 28 and the brake assist force) to the master cylinder 24.

[0020] As a result, the master cylinder 24 generates a master cylinder pressure (brake fluid pressure) corresponding to the thrust transmitted to the input rod 28. The brake fluid pressure generated by the master cylinder 24 is transmitted to the brake fluid pressure circuit 16.

[0021] The master cylinder 24 is connected via a brake fluid pressure circuit 16 to calipers 10fl, 10fr, 10rl, and 10rr provided on the wheels 5fl, 5fr, 5rl, and 5rr, respectively.

[0022] The brake fluid pressure circuit 16 is composed of two systems of fluid pressure lines: a first fluid pressure circuit 32 and a second fluid pressure circuit 33. The brake fluid pressure circuit 16 according to this embodiment is of a cross piping (X piping) type in which the first fluid pressure circuit 32 and the second fluid pressure circuit 33 are piped so as to intersect in a diagonal direction of the vehicle M. That is, in the brake fluid pressure circuit 16 according to this embodiment, the first fluid pressure circuit 32 is connected to the calipers 10fl, 10rr of the left front wheel and the right rear wheel arranged in one diagonal direction of the vehicle M, and the second fluid pressure circuit 33 is connected to the calipers 10fr, 10rl of the right front wheel and the left rear wheel arranged in the other diagonal direction of the vehicle M.

[0023] Since the first hydraulic circuit 32 and the second hydraulic circuit 33 have the same configuration, the same reference numerals will be used appropriately to simplify the description below. In addition, when describing the configuration of the brake hydraulic circuits 32 and 33 below, for convenience, the master cylinder 24 side will be described as upstream and the caliper 10fl, 10fr, 10rl, and 10rr side will be described as downstream, based on the flow from the master cylinder 24 to the caliper 10fl, 10fr, 10rl, and 10rr side of the brake caliper.

[0024] Each hydraulic circuit 32, 33 is connected to a first and second supply / discharge port 24a, 24b provided in the master cylinder 24. Specifically, each supply / discharge port 24a, 24b is connected to the upstream of a first hydraulic passage L1 constituting each hydraulic circuit 32, 33. The downstream of the first hydraulic passage L1 is connected to the middle of a second hydraulic passage L2. The upstream side of the second hydraulic passage L2 is connected to a low-pressure accumulator 34 serving as a pressure accumulation means.

[0025] The downstream side of the second fluid path L2 is branched and connected to a third fluid path L3 and a fourth fluid path L4. Furthermore, the downstream side of each fluid path L3, L4 is connected to a caliper 10fl, 10rr (10fr, 10rl) that operates the friction brakes 6fl, 6rr (6fr, 6rl) provided on each wheel 5fl, 5rr (5fr, 5rl) to generate a braking force (friction braking force) on each wheel 5fl, 5rr (5fr, 5rl).

[0026] Meanwhile, the upstream of the fifth and sixth fluid paths L5 and L6 are connected to the middle of the third and fourth fluid paths L3 and L4. The downstream of these fifth and sixth fluid paths L5 and L6 is connected to a seventh fluid path, and the downstream of this seventh fluid path L7 is connected to the low-pressure accumulator 34.

[0027] A gate-in valve 35 is provided in the first hydraulic line L1, and a hydraulic pump 36 is provided in the second hydraulic line L2 downstream of the first hydraulic line L1. Furthermore, the hydraulic pumps 36 of the first and second hydraulic circuits 32, 33 are connected to a common electric motor 37.

[0028] The drive shafts of the hydraulic pumps 36, 36 are connected to an electric motor 37 so that the hydraulic pressure pulsations generated by the hydraulic pumps 36, 36 are in opposite phases to each other.

[0029] The first fluid line L1 upstream of the gate-in valve 35 and the second fluid line L2 downstream of the hydraulic pump 36 are bypass-connected via an eighth fluid line L8. A bypass valve 38 is provided in the eighth fluid line L8. A first brake fluid pressure sensor 39a (a second brake fluid pressure sensor 39b) is provided in the second fluid line L2 downstream of the eighth fluid line L8. The brake fluid pressure sensor 39a (39b) is, for example, a fluid pressure sensor that detects the hydraulic pressure of the brake fluid acting on the second fluid line L2. Pressurizing valves 40 and 41 are provided in the third and fourth fluid lines L3 and L4, and decompressing valves 42 and 43 are provided in the fifth and sixth fluid lines L5 and L6.

[0030] The valves 35, 38, 40 to 43 are, for example, electromagnetic solenoid valves. The valves 35, 33, 40 to 43 and the electric motor 37 are controlled and driven by the BCU 8.

[0031] In this embodiment, for example, the bypass valve 38 and the pressurizing valves 40 and 41 are configured by normally open electromagnetic solenoid valves, and the gate-in valve 35 and the pressure reducing valves 42 and 43 are configured by normally closed electromagnetic solenoid valves.

[0032] Therefore, under normal circumstances when the BCU 8 is not controlling each of the valves 35, 38, 40 to 43 and the electric motor 37, the brake fluid pressure generated in the master cylinder 24 in accordance with the driver's depression of the brake pedal 26 is basically supplied to each caliper 10 as is.

[0033] On the other hand, for example, in a vehicle M equipped with a driving assistance device or the like (not shown), the BCU 8 drives the electric motor 37 as necessary, opens the gate-in valve 35, and closes the bypass valve 38. As a result, the pressure medium pressurized in the master cylinder 24 or the pressure medium supplied directly from the reservoir tank 25 is pressurized to a predetermined brake hydraulic pressure via the hydraulic pump 36, and then supplied from the second hydraulic line L2 to the third and fourth hydraulic lines L3 and L4.

[0034] Furthermore, for example, during braking force cooperative control in which the brakes are coordinated with the regenerative brake and the engine brake, the BCU 8 controls the driving of the pressure reducing valves 42, 43 and the electric motor 37 as necessary to reduce the brake fluid pressure, thereby controlling the friction braking force to a braking force according to a predetermined braking force distribution value.

[0035] Next, the detailed configuration of the brake pedal mechanism 15, centering on the slider mechanism 29, will be described with reference to FIGS.

[0036] A pedal bracket 30 extending toward the passenger compartment of the vehicle M is fixed to the brake booster 27.

[0037] One end (upper end) of a pedal arm 26a constituting the brake pedal 26 is rotatably connected to the tip end side of the pedal bracket 30 via an arm rotation shaft 26b. That is, the brake pedal 26 is rotatably supported on the pedal bracket 30 with the arm rotation shaft 26b as a fulcrum. A foot pedal 26c is provided on the other end (lower end) of the pedal arm 26a.

[0038] Further, one end of a rod guide 31 is fixed to the middle of the pedal bracket 30 by bolting or the like.

[0039] A rod insertion hole 31a is provided at the other end of the rod guide 31. The input rod 28 extending from the brake booster 27 is inserted into the rod insertion hole 31a. This allows the input rod 28 to move linearly relative to the brake booster 27, but prohibits it from swinging relative to the brake booster 27. In other words, the rod guide 31 allows the input rod 28 to move back and forth in a direction along the central axis of the input rod 28, but prohibits it from swinging in a direction intersecting the central axis of the input rod 28.

[0040] The slider mechanism 29 is composed of a guide rail 51 provided midway along the pedal arm 26a, a slider 52 that is movable on the guide rail 51, and a connecting arm 53 that connects the slider 52 to the input rod 28.

[0041] The guide rail 51 is disposed on the rear side (toe board side of the vehicle M) of the pedal arm 26a. The guide rail 51 extends along the longitudinal direction of the pedal arm 26a. As shown in Fig. 5, the guide rail 51 is provided with a rack gear 51a.

[0042] As shown in FIG. 5, the slider 52 includes therein a motor 52a as an actuator and a worm gear 52b fixed to the rotation shaft of the motor 52a.

[0043] The motor 52a is configured by, for example, a stepping motor, etc. The motor 52a is controlled and driven by the BCU 8.

[0044] Furthermore, the worm gear 52b is meshed with the rack gear 51a of the guide rail 51. As a result, the worm gear 52b transmits the driving force of the motor 52a to the rack gear 51a.

[0045] Therefore, when the motor 52a is driven based on a control signal from the BCU 8, the slider 52 moves on the guide rail 51. The slider 52 is held at the position on the guide rail 51 when the motor 52a is stopped.

[0046] One end of the connecting arm 53 is rotatably connected to the slider 52 via a first rotating shaft 53a.

[0047] The other end of the connecting arm 53 is rotatably connected to the tip of the input rod 28 via a second rotating shaft 53b.

[0048] As a result, the connecting arm 53 connects the slider 52 (pedal arm 26a) and the input rod 28 while allowing the slider 52 to move on the guide rail 51. Furthermore, since the slider 52 is held at any position on the guide rail 51 and the input rod 28 is prohibited from swinging by the rod guide 31, the connecting arm 53 transmits the pedal force applied when the brake pedal 26 is depressed to the input rod 28 as a thrust.

[0049] In the brake pedal mechanism 15 configured as above, the brake pedal 26 functions with the arm rotation shaft 26b as a fulcrum, the foot pedal 26c as a force point, and the first rotation shaft 53a as a point of application. As a result, the pedal force input to the brake pedal 26 is converted into thrust at a predetermined lever ratio Lr and transmitted to the input rod 28.

[0050] In such a brake pedal mechanism 15, the first rotation shaft 53a moves in accordance with the movement of the slider 52 on the guide rail 51. This allows the brake pedal mechanism 15 to change the lever ratio Lr of the brake pedal 26.

[0051] Here, the lever ratio Lr of the brake pedal 26 in this embodiment is defined by the following equation (1), for example, where Lp is the distance from the arm rotation shaft 26b to the foot pedal 26c and La is the distance from the arm rotation shaft 26b to the first rotation shaft 53a.

[0052] Lr = Lp / La … (1)

[0053] Therefore, if the pedal force input to the foot pedal 26c is Fp, the thrust Fin transmitted to the input rod 28 is calculated by the following equation (2).

[0054] Fin = Fp Lr = Fp (Lp / La) …(2)

[0055] 2, the center of the guide rail 51 is set as the neutral position (reference position) of the slider 52. At this neutral position, a reference lever ratio Lf is set.

[0056] In contrast, for example, as shown in FIG. 3, when the slider 52 moves from the neutral position toward the arm pivot shaft 26b, the distance Lp remains unchanged, and only the distance La decreases. Therefore, when the slider 52 moves from the neutral position toward the arm pivot shaft 26b, the lever ratio Lr becomes relatively larger compared to when the slider 52 is in the neutral position. This allows the driver to perform a brake operation with a relatively small pedal force. That is, as the lever ratio Lr increases, the thrust force Fin input to the input rod 28 becomes larger relative to the pedal force Fp transmitted to the brake pedal 26. In other words, a brake operation to generate a desired braking force (brake fluid pressure) requires a longer pedal stroke than when the slider 52 is in the neutral position, but can be achieved with a small pedal force.

[0057] On the other hand, for example, as shown in FIG. 4, when the slider 52 moves from the neutral position toward the foot pedal 26c (the side opposite the arm pivot shaft 26b), the distance Lp remains unchanged, but only the distance La increases. Therefore, when the slider 52 moves toward the foot pedal 26c from the neutral position, the lever ratio Lr becomes relatively smaller than when the slider 52 is in the neutral position. This requires the driver to apply a relatively large pedal force to brake. In other words, due to the decrease in the lever ratio Lr, the thrust force Fin input to the input rod 28 becomes relatively smaller compared to the pedal force Fp transmitted to the brake pedal 26. In other words, a brake operation to generate a desired braking force (brake fluid pressure) can be achieved with a shorter pedal stroke than when the slider 52 is in the neutral position, but a larger pedal force is required.

[0058] In this way, the brake pedal mechanism 15 of this embodiment is capable of arbitrarily changing the operation characteristics (relationship between the depression force and the thrust force) of the brake pedal 26 by the slider mechanism 29.

[0059] As shown in FIG. 1, the input side of the BCU 8 is connected to the above-mentioned first and second brake fluid pressure sensors 39a, 39b, a brake switch 61, a negative pressure sensor 62, and an operation panel 63.

[0060] The brake switch 61 is configured as a switch that is turned on when the driver depresses the brake pedal 26. Furthermore, the negative pressure sensor 62 detects the negative pressure (booster pressure Pb) introduced from a negative pressure source to the brake booster 27. Furthermore, the operation panel 63 functions as a setting means that can arbitrarily set the operation characteristics (i.e., lever ratio Lr) of the brake pedal 26.

[0061] Based on these input signals, the BCU 8 controls the slider mechanism 15 .

[0062] For example, when the booster pressure Pb detected by the negative pressure sensor 62 is less than a preset threshold value Pbth, the BCU 8 determines that there is a possibility that the brake booster 27 has failed.

[0063] Also, for example, when the brake fluid pressure Ph detected by the first and second brake pressure sensors 39a, 39b is less than a predetermined threshold value Phth even though the brake switch 61 is turned on, the BCU8 determines that there is a possibility that the brake booster 27 has failed.

[0064] While such a malfunction is being determined, the BCU 8 moves the slider 52 to a pedaling force reduction position that is set closer to the arm rotation shaft 26b than the neutral position.

[0065] Furthermore, if it is determined that there is no possibility that the brake booster 27 has failed, and an arbitrary lever ratio Lr is set by the operation panel 63, the BCU 8 moves the slider 52 to a change request position according to the lever ratio Lr.

[0066] Next, the position control of the slider 52 on the guide rail 51 will be described with reference to the flowchart of the slider position control routine shown in FIG.

[0067] This routine is repeatedly executed at set time intervals. When the routine starts, in step S101, the BCU 8 checks whether the booster pressure Pb is equal to or greater than a preset threshold value Pbth based on a signal from the vacuum sensor 62. That is, the BCU 8 checks whether the booster pressure Pb stored in the brake booster 27 is sufficient to amplify the thrust transmitted to the input rod 28.

[0068] If it is determined in step S101 that the booster pressure Pb is less than the threshold value Pbth, the BCU 8 proceeds to step S104.

[0069] On the other hand, if it is determined in step S101 that the booster pressure Pb is equal to or greater than the threshold value Pbth, the BCU 8 proceeds to step S102.

[0070] In step S102, the BCU 8 checks whether the brake switch 61 is turned on, that is, whether the driver is depressing the brake pedal 26.

[0071] Then, if it is determined in step S103 that the brake switch 61 is turned off, the BCU 8 proceeds to step S105.

[0072] On the other hand, if it is determined in step S103 that the brake switch 61 is turned on, the BCU 8 proceeds to step S103.

[0073] In step S103, the BCU 8 checks whether the brake fluid pressure Ph is equal to or greater than a preset threshold value Phth based on the signals from the first and second brake fluid pressure sensors 39a, 39b.

[0074] Then, in step S103, if it is determined that the brake fluid pressure Ph is equal to or greater than the threshold value Phth, that is, if it is determined that an appropriate brake fluid pressure Ph is being generated in response to the driver's brake operation, the BCU 8 proceeds to step S105.

[0075] On the other hand, if it is determined in step S103 that the brake fluid pressure Ph is less than the threshold value Phth, that is, if it is determined that the expected appropriate brake fluid pressure Ph is not being generated despite the driver's brake operation, the BCU 8 proceeds to step S104. Note that a case in which the brake fluid pressure Ph is less than the threshold value Phth may be, for example, when a sufficient brake assist force for the thrust is not being generated due to some malfunction of the brake booster 27 despite the booster pressure Pb being generated appropriately.

[0076] When the process proceeds from step S101 or step S103 to step S104, the BCU 8 determines that there is some kind of malfunction in the brake booster 27, and then proceeds to step S105.

[0077] When the process proceeds from step S102 or step S104 to step S105, the BCU 8 checks whether or not it has been determined that the brake booster 27 has a malfunction.

[0078] If it is determined that a malfunction has occurred in the brake booster 27, the BCU 8 proceeds from step S105 to step S106. In step S106, the BCU 8 moves the slider 52 to a pedal force reduction position set closer to the arm rotation shaft 26b than the neutral position, and then exits the routine.

[0079] On the other hand, if it is not determined that a malfunction has occurred in the brake booster 27, the BCU 8 proceeds from step S105 to step S107.

[0080] In step S107, the BCU 8 checks, based on a signal from the operation panel 63, whether or not a request to change the lever ratio Lr of the brake pedal 26 has been made by the driver.

[0081] If it is determined in step S107 that a request to change the lever ratio Lr has not been made, the BCU 8 proceeds to step S108. In step S108, the BCU 8 controls the slider 52 to the neutral position, and then exits the routine.

[0082] On the other hand, if it is determined in step S107 that a request to change the lever ratio Lr has been made, the BCU 8 proceeds to step S109. In step S109, the BCU 8 controls the slider 52 to a position according to the requested lever ratio Lr, and then exits the routine.

[0083] According to this embodiment, the brake device 1 includes a guide rail 51 provided on the pedal arm 26a and extending along the longitudinal direction of the pedal arm 26a, a slider 52 connected to the pedal arm 26a via the guide rail 51 and movable on the guide rail 51, and a connecting arm 53 having one end rotatably connected to the slider 52 and the other end rotatably connected to the input rod 28.

[0084] This allows the relationship between the pedal force Fp input to the brake pedal 26 and the thrust force Fin transmitted to the input rod 28 to be changed as desired.

[0085] That is, the brake device 1 can change the lever ratio Lr of the brake pedal 26 to any desired lever ratio by arbitrarily changing the position of the point of application of the brake pedal 26 by moving the slider 52.

[0086] In this case, the brake device 1 is configured to change the lever ratio Lr by changing the position of the slider 52 on the guide rail 51. Therefore, even after changing the lever ratio Lr, the entire length of the brake pedal 26 can be effectively utilized.

[0087] Furthermore, in the event of a malfunction of the brake booster 27, such as when the negative pressure (booster pressure Pb) introduced into the brake booster 27 falls below a preset threshold value Pbth, the brake device 1 moves the slider 52 toward the arm pivot shaft 26b to reduce the lever ratio Lr. This allows brake fluid pressure to be generated with a relatively small pedal force Fp, even when an appropriate assist force is not generated in response to the thrust transmitted to the input rod 28.

[0088] Furthermore, the brake device 1 sets a desired lever ratio Lr based on an operation input to the operation panel, and moves the slider 52 to a position on the guide rail 51 that corresponds to the set lever ratio Lr. This makes it possible to realize operation characteristics of the brake pedal 26 that match the driver's preferred operation feel.

[0089] Furthermore, the brake device 1 allows the input rod 28 to move back and forth along the central axis thereof by using a rod guide 31 interposed between the brake booster 27 and the slider mechanism 29, while prohibiting the input rod 28 from swinging. As a result, even when the slider mechanism 29 is interposed between the brake pedal 26 and the input rod 28, the pedal force Fp input to the brake pedal 26 can be accurately transmitted to the input rod 28 as a thrust.

[0090] In the above-described embodiment, the BCU8 is configured with a well-known microcomputer equipped with a CPU, RAM, ROM, nonvolatile storage, etc., and its peripheral devices, and the ROM prestores programs to be executed by the CPU, fixed data such as data tables, etc. Note that all or part of the functions of the processor may be configured with logic circuits or analog circuits, and the processing of various programs may be realized by electronic circuits such as FPGAs.

[0091] The invention described in the above embodiments is not limited to these embodiments, and various modifications can be made in the implementation stage without departing from the spirit of the invention.

[0092] For example, as shown in Fig. 7, the guide rail 51 can be formed in an arc shape centered on the second rotation shaft 53b. By forming the guide rail 51 in this manner, the inclination of the brake lever 26 under no load can be maintained constant even when the lever ratio Lr is changed.

[0093] Furthermore, each of the above embodiments includes inventions at various stages, and various inventions can be extracted by appropriate combinations of the disclosed constituent elements.

[0094] For example, if some constituent elements are deleted from all the constituent elements shown in each form, and the stated problem can still be solved and the stated effect can still be obtained, then the configuration from which these constituent elements have been deleted can be extracted as an invention. [Explanation of symbols]

[0095] 1. Brake device 5fl,5fr,5rl,5rr … Wheels 6fl, 6fr, 6rl, 6rr ... friction brake 7... Brake actuator 9fl, 9fr, 9rl, 9rr ... disc rotor 10fl, 10fr, 10rl, 10rr... caliper 15...Brake pedal mechanism 15... Slider mechanism 16... Brake fluid pressure circuit 24... Master cylinder 24a, 24b ... Intake and discharge ports 25...Reservoir tank 26...Brake pedal 26a ... Pedal arm 26b ... Arm rotation axis 26c ... Foot pedal 27... Brake booster 27a ... Negative pressure pipe 28... Input rod 29 ... Slider mechanism 30... Pedal bracket 31 ... Rod guide 31a ... Rod insertion hole 32, 33 ... Brake fluid pressure circuit 39a ... First brake fluid pressure sensor 39b ... Second brake fluid pressure sensor 51 ... guide rail 51a ... rack gear 52 ... slider 52a ... Motor 52b...worm gear 53 ... Connecting arm 53a ... First rotation axis 53b ... Second rotation axis 61 ... Brake switch 62 ... Negative pressure sensor 63 ... Operation panel Fin... Thrust Fp: pedal force La... distance Lf … Lever ratio Lp … distance Lr... Lever ratio M... Vehicle

Claims

1. a brake pedal that is rotatable about an arm rotation shaft provided at one end of the pedal arm; an input rod to which a pedal force input to the brake pedal is transmitted as a thrust; a master cylinder that generates a brake fluid pressure according to the thrust input to the input rod; a guide rail provided on the pedal arm and extending along the longitudinal direction of the pedal arm; a slider connected to the pedal arm via the guide rail and movable on the guide rail; a connecting arm having one end rotatably connected to the slider and the other end rotatably connected to the input rod; a vacuum type brake booster that increases the thrust transmitted to the input rod; a negative pressure sensor for detecting a negative pressure introduced into the brake booster; a control means for controlling the movement position of the slider relative to the guide rail; Equipped with the control means moves the slider toward the arm rotation shaft when the negative pressure detected by the negative pressure sensor is less than a preset threshold value; A brake device characterized by:

2. a setting means for setting operation characteristics of the brake pedal; 2. The brake device according to claim 1, wherein the control means moves the position of the slider on the guide rail to a position corresponding to the set operation characteristics when the negative pressure detected by the negative pressure sensor is equal to or greater than the threshold value.

3. a rod guide for guiding the input rod; 3. The brake device according to claim 1, wherein the rod guide allows the input rod to move back and forth along a central axis of the input rod, and prohibits the input rod from swinging in a direction intersecting the central axis.

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